US11854523B2 - Sound absorber, sound absorbing panel and sound absorbing wall - Google Patents

Sound absorber, sound absorbing panel and sound absorbing wall Download PDF

Info

Publication number
US11854523B2
US11854523B2 US18/296,656 US202318296656A US11854523B2 US 11854523 B2 US11854523 B2 US 11854523B2 US 202318296656 A US202318296656 A US 202318296656A US 11854523 B2 US11854523 B2 US 11854523B2
Authority
US
United States
Prior art keywords
sound absorbing
region
cavity
absorbing unit
sound
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
US18/296,656
Other languages
English (en)
Other versions
US20230260496A1 (en
Inventor
Masaki GOMI
Yudai TAIRA
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pixie Dust Technologies Inc
Original Assignee
Pixie Dust Technologies Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from PCT/JP2022/026161 external-priority patent/WO2023013323A1/ja
Application filed by Pixie Dust Technologies Inc filed Critical Pixie Dust Technologies Inc
Assigned to Pixie Dust Technologies, Inc. reassignment Pixie Dust Technologies, Inc. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: GOMI, MASAKI, TAIRA, Yudai
Publication of US20230260496A1 publication Critical patent/US20230260496A1/en
Application granted granted Critical
Publication of US11854523B2 publication Critical patent/US11854523B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01F—ADDITIONAL WORK, SUCH AS EQUIPPING ROADS OR THE CONSTRUCTION OF PLATFORMS, HELICOPTER LANDING STAGES, SIGNS, SNOW FENCES, OR THE LIKE
    • E01F8/00—Arrangements for absorbing or reflecting air-transmitted noise from road or railway traffic
    • E01F8/0005—Arrangements for absorbing or reflecting air-transmitted noise from road or railway traffic used in a wall type arrangement
    • E01F8/0047—Arrangements for absorbing or reflecting air-transmitted noise from road or railway traffic used in a wall type arrangement with open cavities, e.g. for covering sunken roads
    • E01F8/0064—Perforated plate or mesh, e.g. as wall facing
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/172—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using resonance effects
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01B—PERMANENT WAY; PERMANENT-WAY TOOLS; MACHINES FOR MAKING RAILWAYS OF ALL KINDS
    • E01B19/00—Protection of permanent way against development of dust or against the effect of wind, sun, frost, or corrosion; Means to reduce development of noise
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01F—ADDITIONAL WORK, SUCH AS EQUIPPING ROADS OR THE CONSTRUCTION OF PLATFORMS, HELICOPTER LANDING STAGES, SIGNS, SNOW FENCES, OR THE LIKE
    • E01F8/00—Arrangements for absorbing or reflecting air-transmitted noise from road or railway traffic
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
    • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
    • E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
    • E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
    • E04B1/84—Sound-absorbing elements
    • E04B1/8404—Sound-absorbing elements block-shaped
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
    • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
    • E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
    • E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
    • E04B1/84—Sound-absorbing elements
    • E04B2001/8414—Sound-absorbing elements with non-planar face, e.g. curved, egg-crate shaped
    • E04B2001/8419—Acoustical cones or the like, e.g. for anechoic chambers
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
    • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
    • E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
    • E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
    • E04B1/84—Sound-absorbing elements
    • E04B2001/8457—Solid slabs or blocks
    • E04B2001/8476—Solid slabs or blocks with acoustical cavities, with or without acoustical filling
    • E04B2001/848—Solid slabs or blocks with acoustical cavities, with or without acoustical filling the cavities opening onto the face of the element

Definitions

  • the present disclosure relates to technology for reducing sound by absorbing sound.
  • Japanese Patent Application Publication 2017-115572 discloses installing a soundproof panel using a sound absorber next to a noise source in order to suppress noise caused by vehicles traveling on roads and railroad tracks.
  • the sound absorbing structure described in Wu (2019) exhibits a sound absorbing effect by having a waveguide extending in the incident direction of sound waves. Therefore, if the waveguide is lengthened in order to efficiently absorb sound in the low frequency band, the thickness of the sound absorbing structure in the incident direction of the sound wave will increase. On the other hand, in order to improve ease of installation of the sound absorber, it is required to reduce the thickness of the sound absorber.
  • FIG. 1 A is a diagram showing the structure of a sound absorbing unit
  • FIG. 1 B is a diagram showing the structure of a sound absorbing unit
  • FIG. 2 A is a diagram showing the structure of a sound absorbing unit
  • FIG. 2 B is a diagram showing the structure of a sound absorbing unit
  • FIG. 3 A is a diagram showing the structure of a chamber member
  • FIG. 3 B is a diagram showing the structure of a chamber member
  • FIG. 4 A is a diagram showing the structure of a chamber member
  • FIG. 4 B is a diagram showing the structure of a chamber member
  • FIG. 5 is a diagram for explaining the function of the sound absorbing unit
  • FIG. 6 is a diagram showing a usage example of the sound absorbing unit
  • FIG. 7 is a diagram showing a usage example of the sound absorbing unit
  • FIG. 8 is a diagram showing a configuration example of a design device
  • FIG. 9 is a diagram showing design processing of a sound absorbing unit by a design device.
  • FIG. 10 A is a diagram showing a modification of the structure of the sound absorbing unit
  • FIG. 10 B is a diagram showing a modification of the structure of the sound absorbing unit
  • FIG. 11 A is a diagram showing a modification of the structure of the sound absorbing unit
  • FIG. 11 B is a diagram showing a modification of the structure of the sound absorbing unit
  • FIG. 12 A is a diagram showing a modification of the structure of the chamber member
  • FIG. 12 B is a diagram showing a modification of the structure of the chamber member
  • FIG. 13 A is a diagram showing a modification of the structure of the chamber member
  • FIG. 13 B is a diagram showing a modification of the structure of the chamber member
  • FIG. 14 is a diagram showing a modification of the structure of the perforated plate
  • FIG. 15 A is a diagram showing a modification of the structure of the sound absorbing unit
  • FIG. 15 B is a diagram showing a modification of the structure of the sound absorbing unit
  • FIG. 16 A is a diagram showing a modification of the structure of the chamber member
  • FIG. 16 B is a diagram showing a modification of the structure of the chamber member
  • FIG. 17 A is a diagram showing the appearance of a modification of the sound absorbing unit
  • FIG. 17 B is a diagram showing the appearance of a modification of the sound absorbing unit
  • FIG. 18 A is a cross-sectional view showing the structure of a modification of the sound absorbing unit
  • FIG. 18 B is a cross-sectional view showing the structure of a modification of the sound absorbing unit
  • FIG. 19 A is a diagram showing the appearance of a modification of the sound absorbing unit
  • FIG. 19 B is a diagram showing the appearance of a modification of the sound absorbing unit
  • FIG. 20 A is a cross-sectional view showing the structure of a modification of the sound absorbing unit
  • FIG. 20 B is a cross-sectional view showing the structure of a modification of the sound absorbing unit
  • FIG. 21 A is a diagram showing the appearance of a modification of the sound absorbing unit
  • FIG. 21 B is a diagram showing the appearance of a modification of the sound absorbing unit
  • FIG. 22 A is a cross-sectional view showing the structure of a modification of the sound absorbing unit
  • FIG. 22 B is a cross-sectional view showing the structure of a modification of the sound absorbing unit
  • FIG. 23 A is a diagram showing the appearance of a modification of the sound absorbing unit
  • FIG. 23 B is a diagram showing the appearance of a modification of the sound absorbing unit
  • FIG. 24 A is a sectional view showing the structure of a modification of the sound absorbing unit
  • FIG. 24 B is a sectional view showing the structure of a modification of the sound absorbing unit
  • FIG. 25 A is a diagram showing the appearance of a modification of the sound absorbing unit
  • FIG. 25 B is a diagram showing the appearance of a modification of the sound absorbing unit
  • FIG. 26 A is a cross-sectional view showing the structure of a modification of the sound absorbing unit
  • FIG. 26 B is a cross-sectional view showing the structure of a modification of the sound absorbing unit
  • FIG. 27 A is a diagram showing the appearance and structure of a modification of the sound absorbing unit
  • FIG. 27 B is a diagram showing the appearance and structure of a modification of the sound absorbing unit
  • FIG. 28 is a diagram showing the structure of a modification of the sound absorbing unit
  • FIG. 29 A is a diagram showing the structure of a modification of the sound absorbing unit
  • FIG. 29 B is a diagram showing the structure of a modification of the sound absorbing unit
  • FIG. 30 A is a diagram showing the structure of a sound absorbing wall using a modification of the sound absorbing unit
  • FIG. 30 B is a diagram showing the structure of a sound absorbing wall using a modification of the sound absorbing unit
  • FIG. 31 A is a diagram showing an overview of a modification of the sound absorbing unit.
  • FIG. 31 B is a diagram showing an overview of a modification of the sound absorbing unit
  • FIG. 32 A is a diagram showing the structure of a modification of the sound absorbing unit.
  • FIG. 32 B is a diagram showing the structure of a modification of the sound absorbing unit.
  • a sound absorber includes a plurality of cavities mutually different in at least one of shape and size.
  • a wall of a first cavity included in the plurality of cavities includes a first region and a second region.
  • a plurality of through-holes connecting an interior of the first cavity to an exterior of the first cavity is formed in the first region. No through-holes connecting the interior of the first cavity and the exterior of the first cavity is formed in the second region adjacent to the first region.
  • a wall of a second cavity included in the plurality of cavities includes a third region and a fourth region.
  • a plurality of through-holes connecting an interior of the second cavity to an exterior of the second cavity is formed in the third region. No through-holes connecting the interior of the second cavity and the exterior of the second cavity is formed in the fourth region adjacent to the third region. Size of through-holes in the first region is different from size of through-holes in the third region.
  • a sound absorber comprising a plurality of cavities different in at least one of shape and size.
  • a wall of a first cavity included in the plurality of cavities includes a first region and a second region.
  • a plurality of through-holes connecting an interior of the first cavity to an exterior of the first cavity is formed in the first region. No through-holes connecting the interior of the first cavity and the exterior of the first cavity is formed in the second region adjacent to the first region.
  • a wall of a second cavity included in the plurality of cavities includes a third region and a fourth region.
  • the sound absorbing unit 10 corresponds to a sound absorber that has a specific sound absorbing structure.
  • the sound absorber has a sound absorbing effect of reducing the sound pressure of reflected sound and transmitted sound by converting the energy of sound waves traveling toward the sound absorbing unit 10 into other energy or canceling it.
  • FIG. 1 A and FIG. 1 B are a perspective view and a front view, respectively, showing the structure of the sound absorbing unit according to the embodiment.
  • FIG. 2 A and FIG. 2 B are a side view and a bottom view, respectively, showing the structure of the sound absorbing unit according to the embodiment.
  • “D direction” is the depth direction (thickness direction) of the sound absorbing unit 10 .
  • the sound absorbing unit 10 mainly absorbs sound waves traveling in the D direction.
  • the “H direction” is a direction substantially perpendicular to the D direction and is the height direction of the sound absorbing unit 10 .
  • the “W direction” is a direction orthogonal to the “D direction” and the “H direction” and is the width direction of the sound absorbing unit 10 .
  • the sound absorbing unit 10 has a plurality of cavities (hereinafter referred to as “waveguides”) through which sound waves can enter, and each waveguide functions as a resonator.
  • the sound absorbing unit 10 has a perforated plate 20 , which is a plate member having through-holes, and a chamber member 40 that is combined with the perforated plate 20 to form a cavity.
  • the surface of the perforated plate 20 has perforated regions 21 to 27 each having a plurality of through-holes and non-perforated regions 31 to 36 having no through-holes.
  • the sound absorbing unit 10 has a polygonal (specifically hexagonal) shape as viewed from the ⁇ D direction.
  • FIGS. 3 A and 3 B are respectively a perspective view and a front view showing the structure of the chamber member according to the embodiment.
  • FIGS. 4 A and 4 B are a side view and a bottom view, respectively, showing the structure of the chamber member according to the embodiment.
  • the chamber member 40 has spaces 41 - 44 separated from each other by partition walls 45 - 47 . By providing the perforated plate 20 so as to cover the chamber member 40 from the ⁇ D direction side, the spaces 41 to 44 become waveguides whose walls are formed by the chamber member 40 and the perforated plate 20 , respectively.
  • space 41 is covered by perforated region 21 , non-perforated region 31 adjacent to perforated region 21 , and perforated region 22 not adjacent to perforated region 21 but adjacent to non-perforated region 31 .
  • Space 42 is covered by non-perforated region 32 , perforated region 23 , non-perforated region 33 and perforated region 24 .
  • Space 43 is covered by perforated region 25 and non-perforated region 34 adjacent to perforated region 25 .
  • Space 44 is covered by non-perforated region 35 , perforated region 26 , non-perforated region 36 and perforated region 27 .
  • the waveguide having the space 41 is called the waveguide 11
  • the waveguide having the space 42 is called the waveguide 12
  • the waveguide having the space 43 is called the waveguide 13
  • the waveguide having the space 44 is called the waveguide 14 .
  • the waveguides 11 and 12 are adjacent to each other via a partition 45
  • the waveguides 12 and 13 are adjacent to each other via a partition 46
  • the waveguides 13 and 14 are adjacent to each other via a partition wall 47 . That is, the partition walls 45 to 47 divide the inside of the sound absorbing unit 10 into a plurality of waveguides.
  • each of the waveguides 11 to 14 has a substantially trapezoidal contour as viewed in the ⁇ D direction, and extends substantially parallel to each other.
  • the waveguides 11 and 12 have different shapes and sizes, and the waveguides 13 and 14 have different shapes and sizes.
  • the waveguides 12 and 13 have substantially the same shape and size of the cavities, but differ in the arrangement of the through-holes formed in the respective walls.
  • the waveguides 11 and 14 have substantially the same cavity shape and size, but differ in the arrangement of through-holes formed in the respective walls.
  • the sound absorbing unit 10 may be configured as a whole, or may be configured by combining a plurality of members.
  • the sound absorbing unit 10 may be configured by combining the perforated plate 20 and the chamber member 40 , or the perforated plate 20 and the chamber member 40 may be integrated.
  • the sound absorbing unit 10 may be configured by combining members that configure each waveguide.
  • the sound absorbing unit 10 may have a plurality of waveguides, and the perforated region and the non-perforated region may be present in the member forming the wall of each waveguide. The interior and exterior of each waveguide are communicated through a plurality of through-holes present in the through-hole region, allowing ventilation.
  • the inside and the outside of the waveguide 11 are communicated with each other through a plurality of through-holes formed in the through-hole regions 21 and 22 , and can be ventilated.
  • the interior and exterior of waveguide 12 communicate through a plurality of through-holes formed in perforated regions 23 and 24 .
  • the inside and outside of waveguide 13 communicate with each other through a plurality of through-holes formed in through-hole region 25 .
  • the inside and outside of the waveguide 14 communicate with each other through a plurality of through-holes formed in the through-hole regions 26 and 27 .
  • the perforated surface of the perforated plate 20 forming the walls of the waveguides 11 to 14 is exposed as viewed from the ⁇ D direction.
  • a sound wave arriving from the ⁇ D direction with respect to the sound absorbing unit 10 and incident on the perforated plate 20 enters the inside of each waveguide through a plurality of through-holes formed in the perforated region, travels in the area covered with the non-perforated region to the direction D, and is reflected by the side surface of the chamber member 40 .
  • Each perforated region of the perforated plate 20 functions as an acoustic impedance matching member, and the waveguides 11 to 14 function as resonators having mutually different resonance characteristics.
  • the sound absorbing unit 10 a sound absorbing effect can be obtained in a wide frequency band compared to a sound absorber having a single waveguide.
  • the sound absorption characteristic of the sound absorbing unit 10 in this embodiment is represented by, for example, a sound absorption coefficient for each frequency or an acoustic impedance.
  • the sound absorbing unit 10 may be designed so that the frequency bands of the sound waves absorbed by the waveguides do not overlap each other, or the sound absorbing unit 10 may be designed such that the frequency bands of the sound waves absorbed by the waveguides partially overlap.
  • the volume of waveguide 11 is smaller than the volume of waveguide 12 and the volume of waveguide 13 is larger than the volume of waveguide 14 .
  • the distance between the perforated regions 21 and 22 on the surface of the perforated plate 20 (length L 1 in FIG. 1 B ) is longer than the length of the waveguide 11 in the direction normal to the surface of the perforated plate 20 (thickness L 2 in FIG. 2 B ).
  • the length of the path along which the sound wave travels in a direction non-parallel to the D direction is increased, thereby improving the sound absorption coefficient in the low frequency band, while the depth (i.e., thickness) in the D direction of the sound absorbing unit 10 can be reduced.
  • the length of the non-perforated region 34 in the direction connecting the center of gravity of the perforated region 25 and the center of gravity of the non-perforated region 34 on the surface of the perforated plate 20 (length L 3 in FIG. 1 B ) is longer than the length of the waveguide 13 in the direction normal to the surface of the perforated plate 20 (thickness L 4 in FIG. 2 B ).
  • the length of the path along which the sound wave travels in a direction non-parallel to the D direction is increased, thereby improving the sound absorption coefficient in the low frequency band and reducing the thickness of the sound absorbing unit 10 .
  • the waveguide 11 has an excellent sound absorption coefficient in a high frequency band compared to the waveguide 13 .
  • the waveguide 13 has an excellent sound absorption coefficient in a low frequency band compared to the waveguide 11 .
  • the through-holes are arranged at one location (that is, the perforated region 25 ). Such a configuration can improve the sound absorption coefficient of the waveguide 13 in a low frequency band as compared with the case where the through-holes are arranged in a plurality of locations.
  • the through-holes are distributed in a plurality of locations (that is, the perforated region 21 and the perforated region 22 ).
  • the sound absorbing unit 10 can be constructed using various materials because it exhibits sound absorbing performance depending on its shape and structure.
  • the sound absorbing unit 10 is made of material such as resin, metal, silicon, rubber, polymer, paper, cardboard, wood, or non-woven fabric.
  • the sound absorbing unit 10 may be made of materials other than these materials.
  • the sound absorbing unit 10 may be configured by combining a plurality of members made of different materials.
  • the perforated plate 20 and the chamber member 40 of the sound absorbing unit 10 may be made of different materials.
  • the configuration of the perforated plate 20 will be described. A plurality of through-holes are formed in each of the perforated regions 21 to 27 of the perforated plate 20 .
  • the perforated plate 20 may be configured as a single body, or may be configured by combining a plurality of members.
  • the portion of the perforated plate 20 that covers each waveguide may be composed of a separate member, or each perforated region and each non-perforated region of the perforated plate 20 may be composed of a separate member.
  • the perforated plate 20 may be composed of six triangular plate members.
  • Hole parameters include, for example:
  • the perforated plate By changing the hole parameters of the perforated plate, the acoustic impedance of the sound absorbing unit 10 can be adjusted.
  • the perforated plate has the effect of lowering the Q value by thermoviscous resistance and enabling sound absorption in a wide frequency band.
  • the lengths of the sound absorbing unit 10 in the H direction and the W direction are 10 cm to 50 cm, respectively, and the thickness of the sound absorbing unit 10 in the D direction is 2 cm to 10 cm.
  • the thickness of the perforated plate 20 is 0.5 mm to 3 mm
  • the diameter of the holes present in the perforated plate is set to 0.3 mm to 3 mm.
  • the perforated plate by appropriately setting other parameters such as the number of holes in the perforated plate, it efficiently absorbs (reduces the sound pressure of) the 400 Hz to 1500 Hz sound that is the main component of the sound contained in human conversation. be able to.
  • the average sound absorption coefficient of sound from 400 Hz to 1500 Hz by the sound absorbing unit 10 is higher than the average sound absorption coefficient of sound in other frequency bands (frequency band lower than 400 Hz and frequency band higher than 1500 Hz) by the sound absorbing unit 10 .
  • the sound absorbing characteristics of the sound absorbing unit 10 can be changed.
  • the sound absorbing unit 10 can be designed such that the average sound absorption coefficient for sounds of 1000 Hz to 4000 Hz is higher than the average sound absorption coefficient for sounds in other frequency bands. Further, for example, the sound absorbing unit 10 can be designed so as to efficiently absorb sounds of 200 Hz or more and 2500 Hz or less.
  • the hole parameters of the plurality of through-hole regions of the sound absorbing unit 10 may be different from each other.
  • the hole parameters of perforated region 21 and perforated region 22 may be optimized according to the sound absorption properties required for waveguide 11 .
  • the hole parameters of perforated region 23 and perforated region 24 may be optimized according to the sound absorption properties required for waveguide 12 .
  • the hole parameters of perforated region 25 may be optimized according to the sound absorption properties required for waveguide 13 .
  • the hole parameters of perforated region 26 and perforated region 27 may be optimized according to the sound absorption properties required for waveguide 14 .
  • the through-holes that communicate the interior and exterior of one of the waveguides 11 to 14 and the through-holes that communicate the interior and exterior of the other waveguides may be different in at least one of the hole parameters or the arrangement of holes.
  • the sound absorbing unit 10 can achieve a high sound absorption coefficient in a wide frequency band.
  • the hole parameters of the plurality of perforated regions of the sound absorbing unit 10 may be common.
  • the specifications of the holes of the perforated plate 20 can be unified, so that the manufacturing cost of the perforated plate 20 can be reduced.
  • the surface of the perforated plate 20 is planar in the example of the sound absorbing unit 10 , the shape of the perforated plate 20 is not limited to this.
  • the surface of the perforated plate 20 may be curved or uneven.
  • FIG. 5 is a diagram explaining the function of the sound absorbing unit according to the embodiment.
  • the sound absorbing unit 10 is installed at a position separated in the direction D from the noise source NS that emits the sound to be absorbed.
  • Each waveguide included in the sound absorbing unit 10 absorbs frequency components corresponding to the shape (for example, length or volume) of the waveguide and the hole parameter of the perforated plate, among the sound waves traveling in the direction D from the noise source NS.
  • the sound pressure of the sound wave arriving from the noise source NS to the position on the side more advanced in D direction than the sound absorbing unit 10 is greatly reduced compared to the case where the sound absorbing unit 10 is not installed.
  • FIG. 6 shows the example of use of the sound absorbing unit in the embodiment.
  • a plurality of sound absorbing units 10 are installed in combination so as to form a sound absorbing wall 1 that blocks sound waves traveling from the noise source NS toward the human HMa.
  • the sound absorbing wall 1 is configured by attaching the plurality of sound absorbing units 10 to the support plate 50 so that the surfaces of the perforated plates 20 of the plurality of sound absorbing units 10 (surfaces on which the through-holes are formed) are exposed as viewed from the same direction.
  • the sound absorbing wall 1 Since the sound absorbing wall 1 has a sound insulating effect, by installing the sound absorbing wall 1 , the sound pressure of the sound wave emitted from the noise source NS is greatly reduced when passing through the sound absorbing wall 1 . Thus, the noise felt by the human being HMa who is behind the wall 1 can be reduced.
  • the sound absorbing wall 1 has a sound absorbing effect
  • the sound absorbing wall 1 by installing the sound absorbing wall 1 , compared to the case where a wall made up of conventional members (for example, a concrete wall) is installed at the same position, the volume of the sound reflected by the wall can be reduced. Therefore, the sound pressure of the sound wave emitted from the noise source NS is greatly reduced when reflected by the sound absorbing wall 1 , and the noise felt by the human HMb on the opposite side of the noise source NS from the sound absorbing wall 1 can be reduced.
  • the sound absorbing wall 1 when the sound absorbing wall 1 is installed, the volume of the sound going around the wall due to diffraction becomes smaller than when the wall made of the conventional member is installed at the same position. Due to this effect, the noise felt by the human HMa behind the wall can be reduced.
  • the sound absorbing wall 1 can be used for the following uses, for example.
  • the sound absorbing wall 1 can suppress noise generated by automobiles or trains by being arranged around roads or railroad tracks.
  • the sound absorbing wall 1 can suppress construction noise by being arranged at the construction site.
  • the sound absorbing wall 1 can suppress noise in the building by being used as a wall of the building.
  • the sound absorbing wall 1 is arranged around a person's work place (for example, a work desk) to suppress the noise perceived by the worker and suppress the sound leakage of the noise emitted by the worker to the surroundings.
  • the sound absorbing wall 1 may be placed so as to surround the work place on all four sides, or the sound absorbing wall 1 may be placed so as to surround three directions excluding the direction of the doorway. Alternatively, only one sound absorbing wall 1 may be placed. Alternatively, a work booth may be configured by closing the ceiling of the work place surrounded by the sound absorbing walls 1 on all four sides.
  • the perforated plate 20 and the chamber member 40 can each be made of a light-transmissive material.
  • the light-transmitting material for example, glass or resin material such as acrylic can be used, but the material is not limited to these.
  • at least the outer shell of the sound absorbing unit 10 should be light transmissive. That is, portions of the chamber member 40 other than the partition walls 45 to 47 and the perforated plate 20 are made of a transparent or translucent material.
  • the sound absorbing unit 10 having such a configuration is a sound absorber suitable for use on a wall surface having light transmission properties such as glass or acrylic.
  • the support plate 50 in FIG. 6 For example, consider a case where a screen made of glass or a low partition is used as the support plate 50 in FIG. 6 .
  • the support plate 50 is light transmissive, so the human HMa can be seen through the support plate 50 and visually recognized by the human HMb.
  • the human HMb cannot visually recognize the human HMa. That is, the attachment of the sound absorber impairs the functionality and design of the support plate 50 .
  • the human HMb can visually recognize the human HMa, and the functionality and design of the support plate 50 are maintained.
  • the translucent sound absorbing unit 10 By attaching the translucent sound absorbing unit 10 to the wall surface, it is possible to change the transparency of the wall surface to which it is attached. For example, when no sound absorbing unit is attached to the support plate 50 made of glass, the human HMa and the human HMb on opposite sides of the support plate 50 can visually recognize each other's actions. On the other hand, when the translucent sound absorbing unit 10 is attached to the support plate 50 , the transparency of the sound absorbing wall 1 composed of the sound absorbing unit 10 and the support plate 50 is lower than that of the support plate 50 . As a result, the human HMa and the human HMb can visually recognize each other's existence, but cannot visually recognize the details of their actions.
  • the translucent sound absorbing unit 10 can be realized by using a translucent material for the perforated plate 20 or roughening the surface of the perforated plate 20 .
  • the sound absorbing unit 10 can also be used on a wall surface that does not have light transmittance.
  • a wall surface that does not have light transmittance For example, consider the case of using a screen that is opaque and has a characteristic pattern on its surface as the support plate 50 in FIG. 6 . In this case, if a sound absorber that does not have light transmittance is attached to the support plate 50 , the characteristic pattern will not be visible and the design will be impaired. However, when the light-transmissive sound absorbing unit 10 is attached to the support plate 50 , the characteristic pattern becomes visible and the design is maintained.
  • the perforated plate 20 is drawn opaquely for the sake of simplification of the drawing.
  • the partition walls 45 to 47 are visible through the perforated plate 20 as viewed from the same angles (oblique direction and ⁇ D direction) as these figures.
  • the partition walls 45 to 47 may be made of a light-transmissive material. Thereby, the visibility through the sound absorbing unit 10 can be further improved.
  • FIG. 7 is a diagram showing another usage example of the sound absorbing unit according to the embodiment.
  • the sound pressure in the space SP can be reduced by attaching the plurality of sound absorbing units 10 to the wall surface 60 of the space SP.
  • a sound absorbing panel is configured by adding to the sound absorbing unit 10 a mounting structure that allows the sound absorbing unit 10 to be mounted on the wall surface 60 .
  • a plurality of sound absorbing panels are mounted side by side on the wall surface 60 so that the surfaces of the perforated plates 20 of the plurality of sound absorbing units 10 (surfaces on which the through-holes are formed) are exposed as viewed from the direction normal to the wall surface 60 .
  • the sound absorbing unit 10 can be easily mounted on or removed from the wall surface 60 .
  • the mounting structure for example, a double-sided tape, a screw fixture, a magnet, a hook-and-loop fastener, or a suction cup can be used.
  • the sound absorbing unit 10 If the sound absorbing unit 10 is not installed in the space SP, the sound of the conversation between the human HMc and the human HMd in the space SP reverberates within the space SP and interferes with the conversation between the human HMe and the human HMf in the same space SP.
  • the sound absorbing unit 10 by attaching the sound absorbing unit 10 to the wall surface 60 , the sound incident on the wall surface 60 is absorbed, and the echo of the sound in the space SP can be suppressed. In addition, it is possible to suppress the sound leaking from inside the space SP to the outside of the space SP.
  • the shape of the waveguide and the hole parameters of the perforated plate 20 so that the sound absorbing unit 10 has the desired sound absorption characteristics, the sound of a specific frequency band in the space SP is can be greatly reduced. Thereby, the resonance of the sound in the space SP can be adjusted.
  • the outer shell of the sound absorbing unit 10 can be made light transmissive. Therefore, for example, when the wall surface 60 is made of a light-transmitting material such as glass, it is possible to particularly prevent deterioration of the functionality and design of the space SP.
  • the mounting structure for mounting the sound absorbing unit 10 on the wall surface 60 may be made of a material having light transmittance. In addition, regardless of whether the mounting structure has light transmittance or not, the mounting structure may be provided not on the entire mounting surface of the sound absorbing unit 10 but only on a part of the mounting surface. These configurations can further suppress deterioration of the functionality and design of the space SP.
  • the configuration of the sound absorbing unit 10 is not limited to this example, and the sound absorbing unit 10 does not have to be light transmissive.
  • the sound absorbing unit 10 does not have to be light transmissive.
  • FIG. 8 is a diagram illustrating a configuration example of a design device.
  • the design device 210 includes a storage device 211 , a processor 212 , an input/output interface 213 , and a communication interface 214 .
  • the storage device 211 is configured to store a program and data.
  • the storage device 211 is, for example, a combination of a ROM (read only memory), a RAM (random access memory), and a storage (for example, a flash memory or a hard disk).
  • the programs include, for example, an OS (Operating System) program and an application (for example, web browser) program that executes information processing.
  • Data includes, for example, data and databases referred to in information processing, and data obtained by executing information processing (that is, execution results of information processing).
  • the programs and data stored by the storage device 211 may be provided via a network, or may be provided by being recorded on a computer-readable recording medium.
  • the processor 212 implements the functions of the design device 210 by executing programs stored in the storage device 211 and processing data. At least part of the functions of the design device 210 may be realized by dedicated hardware (for example, ASIC (application specific integrated circuit) or FPGA (field-programmable gate array)).
  • ASIC application specific integrated circuit
  • FPGA field-programmable gate array
  • the input/output interface 213 has a function of receiving an input corresponding to a user's operation on an input device connected to the design device 210 and a function of output information to an output device connected to the design device 210 .
  • the input device is, for example, a keyboard, a pointing device, a touch panel, or a combination thereof.
  • the output device is, for example, a display that displays images or a speaker that outputs audio.
  • a communication interface 214 controls communication between the design device 210 and an external device (e.g., server).
  • FIG. 9 is a diagram showing design processing of the sound absorbing unit by the design device.
  • the processing shown in FIG. 6 is implemented by executing a program stored in the storage device 211 by the processor 212 of the design device 210 . However, at least part of the processing shown in FIG. 6 may be realized by dedicated hardware.
  • the processing shown in FIG. 6 is started in response to the user's input to the design device 210 to start designing the sound absorbing unit 10 . However, the conditions for starting the process shown in FIG. 6 are not limited to this.
  • the design device 210 acquires fixed values that can be set as design parameters of the sound absorbing unit 10 .
  • the processor 212 acquires fixed values by accepting user input or by reading a file in which fixed values are stored.
  • Design parameters of the sound absorbing unit 10 include, for example, at least one of the following:
  • the size of the sound absorbing unit 10 , the number of waveguides, and the shape of the side wall are acquired as fixed values in S 100 .
  • the hole parameters of the perforated plate, the size of the waveguide, and the shape of the waveguide shall be treated as variables.
  • the design device 210 acquires the domain of the design parameter treated as a variable (the possible range of the variable).
  • the processor 212 acquires the domain of the variable by accepting user input or by reading a file in which the domain of the variable is stored.
  • the design device 210 constructs an analysis model of the sound absorbing unit 10 .
  • the processor 212 uses the fixed values acquired in S 100 and the values of the variables selected from the domain acquired in S 101 as design parameters for the analysis model of the sound absorbing unit 10 .
  • the design device 210 evaluates the sound absorption characteristics of the analysis model. Specifically, the processor 212 obtains an evaluation value of the sound absorption characteristics of the analysis model by analyzing the sound absorption characteristics by acoustic simulation using the analysis model constructed in S 102 . For example, the design device 210 acquires the average sound absorption coefficient or average reflectance in each of multiple frequency bands. In addition, the evaluation method of the sound absorption property is not limited to this. For example, the design device 210 may obtain the average transmittance in each of multiple frequency bands.
  • the design device 210 determines the search state. Specifically, the processor 212 determines whether the domain acquired in S 101 has been searched for each variable (that is, the construction and the evaluation of the sound absorption characteristics of the analysis model using all the numerical values that can be selected from the domain have been ended) or not.
  • the process returns to S 102 , the design device 210 selects new variable values from the domain acquired in S 101 , and constructs the analysis model and evaluates the sound absorption characteristics again. On the other hand, if it is determined in S 104 that the search has ended, the process proceeds to S 105 .
  • the design device 210 extracts the optimum values of the variables. Specifically, the processor 212 extracts, as the optimal value, the numerical value of the design parameter corresponding to the analysis model showing the highest evaluation value in the repeatedly performed evaluation of the sound absorption characteristics in S 103 . For example, when 400 Hz to 1000 Hz is specified as the frequency band for sound absorption, the numerical value of the design parameter of the analysis model with the highest average sound absorption coefficient in 400 Hz to 1000 Hz is extracted as the optimum value. By designing the sound absorbing unit 10 using the optimum values thus extracted, it is possible to manufacture the sound absorbing unit 10 having excellent sound absorbing characteristics in the range of 400 Hz to 1000 Hz.
  • the frequency band for sound absorption may be specified in response to user input.
  • the processing flow of FIG. 6 ends.
  • the processes of S 100 and S 101 may be performed in reverse order, or may be performed in parallel.
  • the design device 210 may output information indicating the evaluation result of the analysis model instead of extracting the optimum values of the variables in S 105 or in addition to the processing of S 105 .
  • the design device 210 may output information indicating the sound absorption characteristics of each of the plurality of analysis models constructed in S 102 , or output information indicating the sound absorption characteristics of the analysis model corresponding to the optimum value extracted in S 105 .
  • the information output by the design device 210 may be numerical values indicating sound absorption characteristics, or may be images output to a display device.
  • the sound absorbing unit 10 is designed so as to maximize the sound absorbing performance in a predetermined frequency band.
  • the sound absorbing unit 10 may be designed so as to achieve a designated sound absorbing performance in a predetermined frequency band.
  • the design device 210 extracts the numerical value of the design parameter of the analysis model whose average sound absorption coefficient in the specified frequency band of 400 Hz to 1000 Hz is closest to the specified value (for example, 0.5) as the optimum value.
  • the design device 210 may extract, as the optimum values, the numerical values of the design parameters of the analysis model in which the average sound absorption coefficient of 100 Hz to 500 Hz is higher than the average sound absorption coefficient of 800 Hz to 2000 Hz and the difference between the average sound absorption coefficients is the largest.
  • FIGS. 10 A and 10 B are a perspective view and a front view, respectively, showing the structure of a sound absorbing unit according to a modification.
  • FIGS. 11 A and 11 B are a side view and a bottom view, respectively, showing the structure of a sound absorbing unit according to a modification.
  • FIGS. 12 A and 12 B are respectively a perspective view and a front view showing the structure of a chamber member according to a modification.
  • FIGS. 13 A and 13 B are a side view and a bottom view, respectively, showing the structure of the chamber member according to the modification.
  • the plurality of partition walls extend substantially in the same direction, so that the plurality of waveguides are arranged substantially parallel.
  • a plurality of partition walls divides the interior of the sound absorbing unit 110 into a plurality of waveguides, and each of which extends from a position inside the sound absorbing unit 110 toward the periphery of the sound absorbing unit 110 as viewed from the ⁇ D direction.
  • the sound absorbing unit 110 has a perforated plate 120 , which is a plate member having through-holes, and a chamber member 140 that is combined with the perforated plate 120 to form a cavity.
  • the surface of the perforated plate 120 has a plurality of perforated regions each having a plurality of through-holes and a plurality of non-perforated regions having no through-holes.
  • the sound absorbing unit 110 has a polygonal (specifically hexagonal) shape as viewed from the ⁇ D direction.
  • the chamber member 140 has spaces 141 - 146 separated from each other by partition walls 147 - 152 .
  • the spaces 141 to 146 each become a waveguide having a wall formed by the chamber member 140 and the perforated plate 120 .
  • space 141 is covered by perforated region 121 and non-perforated region 131 adjacent to perforated region 21 .
  • Space 142 is covered by perforated region 122 and non-perforated region 132 .
  • Space 143 is covered by perforated region 123 and non-perforated region 133 .
  • Space 144 is covered by perforated region 124 and non-perforated region 134 .
  • Space 145 is covered by perforated region 125 and non-perforated region 135 .
  • Space 146 is covered by perforated region 126 and non-perforated region 136 .
  • the waveguides having spaces 141 - 146 are hereinafter referred to as waveguides 111 - 116 , respectively.
  • the partition walls 147 - 152 divide the interior of the sound absorbing unit 110 into a plurality of waveguides, and each waveguide is adjacent to the other two waveguides via the partition wall.
  • Partition walls 147 - 152 extend from position 153 toward each vertex of the hexagon as viewed in the ⁇ D direction, and waveguides 111 - 116 each have a triangular shape as viewed in the ⁇ D direction.
  • the waveguides 111 , 116 , and 115 have different shapes and sizes, and the waveguides 112 , 113 and 114 have different shapes and sizes.
  • Waveguide 112 and waveguide 113 have substantially the same cavity shape and size, but differ in the arrangement of through-holes formed in the respective walls.
  • the waveguides 111 and 112 , the waveguides 116 and 113 , and the waveguides 114 and 115 have approximately the same cavity size, but differ in the arrangement of the through-holes formed on their respective walls.
  • the perforated surface of the perforated plate 120 forming the walls of the waveguides 111 to 116 is exposed as viewed from the ⁇ D direction.
  • a sound wave arriving from the ⁇ D direction with respect to the sound absorbing unit 110 and incident on the perforated plate 120 enters the inside of each waveguide through a plurality of through-holes formed in the perforated region, travels in a direction non-parallel to the D direction in the area covered by the non-perforated region, and is reflected by the side surface of the chamber member 140 .
  • Each perforated region of the perforated plate 120 functions as an acoustic impedance matching member, and the waveguides 111 to 116 function as resonators having mutually different resonance characteristics. Therefore, according to the sound absorbing unit 110 , a sound absorbing effect can be obtained in a wide frequency band compared to a sound absorber having a single waveguide.
  • the waveguide 113 has a better sound absorption coefficient in a low frequency band than the waveguide 112
  • the waveguide 114 has a better sound absorption coefficient in a lower frequency band than the waveguide 113
  • the waveguide 116 has a better sound absorption coefficient in a low frequency band than the waveguide 111
  • the waveguide 115 has a better sound absorption coefficient in a lower frequency band than the waveguide 116 .
  • the sound absorbing unit 110 may be designed so that the frequency bands of sound waves absorbed by the waveguides do not overlap each other, or the frequency bands of the sound waves absorbed by the waveguides may be partially overlapped. Unit 110 may be designed.
  • the length of non-perforated region 135 in the direction connecting the center of gravity of perforated region 125 and the center of gravity of non-perforated region 135 is longer than the waveguide 115 (thickness L 6 in FIG. 11 B ) in the direction normal to the surface of the perforated plate 120 .
  • FIG. 14 shows a modification of the perforated plate structure in the sound absorbing unit 110 .
  • a perforated region 221 and a perforated region 222 are newly provided in the perforated plate 220 of FIG. 14 as compared with the perforated plate 120 of FIGS. 10 A and 10 B .
  • the through-holes are arranged at a plurality of locations.
  • Such a configuration can improve the sound absorption coefficient of the waveguide 111 in a high frequency band as compared with the case where the through-holes are arranged in one place (that is, the case where the perforated plate 120 is used).
  • the distance between the perforated regions 125 and 221 on the surface of the perforated plate 220 (length L 7 in FIG. 14 ) is longer than the length of the waveguide 111 in the direction normal to the surface of the perforated plate 220 (which equals to the thickness L 6 in FIG. 11 B ).
  • the length of the path along which the sound wave travels in a direction non-parallel to the D direction is increased, thereby improving the sound absorption coefficient in the low frequency band, while reducing the thickness of the sound absorbing unit 110 .
  • FIGS. 15 A and 15 B are a perspective view and a front view, respectively, showing the structure of a sound absorbing unit according to a modification.
  • FIGS. 16 A and 16 B are diagrams showing the structure of a chamber member according to a modification, respectively.
  • the plurality of partition walls extend substantially in the same direction, so that the plurality of waveguides are arranged substantially parallel.
  • a plurality of partition walls divide the interior of the sound absorbing unit 310 into a plurality of waveguides, and some of which extend in the H direction as viewed from the ⁇ D direction, and the remainder extends in the W direction. That is, a plurality of waveguides are arranged in the H direction and the W direction.
  • the sound absorbing unit 310 includes a perforated plate 320 , which is a plate member having through-holes, and a chamber member 340 that is combined with the perforated plate 320 to form a cavity.
  • the surface of the perforated plate 320 has a perforated region 321 with a plurality of through-holes and non-perforated regions 331 and 332 without through-holes.
  • the sound absorbing unit 110 has a polygonal (more specifically, quadrangular) shape as viewed from the ⁇ D direction.
  • chamber member 340 has spaces 341 - 344 partitioned from each other by partition walls 345 - 347 .
  • the spaces 341 to 344 become waveguides whose walls are formed by the chamber member 340 and the perforated plate 320 , respectively.
  • the spaces 341 to 344 are each covered by a perforated region 321 and a non-perforated region 331 and a non-perforated region 332 adjacent to the perforated region 321 on opposite sides.
  • the waveguides having spaces 341 - 344 are hereinafter referred to as waveguides 311 - 314 , respectively.
  • the partition walls 345 - 347 divide the interior of the sound absorbing unit 310 into a plurality of waveguides, and each waveguide is adjacent to two or three other waveguides through the partition walls.
  • the partition walls 345 to 347 extend in the H direction or W direction as viewed from the ⁇ D direction, and the waveguides 311 to 314 each have a rectangular shape as viewed from the ⁇ D direction.
  • the waveguides 311 - 314 differ from each other in shape and size.
  • the perforated surface of the perforated plate 320 forming the walls of the waveguides 311 to 314 is exposed as viewed from the ⁇ D direction.
  • a sound wave arriving from the ⁇ D direction with respect to the sound absorbing unit 310 and incident on the perforated plate 320 enters the inside of each waveguide through a plurality of through-holes formed in the perforated region, travels non-parallel to the D direction in the area covered by the non-perforated region, and is reflected by the side surface of the chamber member 340 .
  • the perforated region 321 of the perforated plate 320 functions as an acoustic impedance matching member, and the waveguides 311 to 314 function as resonators having mutually different resonance characteristics. Therefore, according to the sound absorbing unit 310 , a sound absorbing effect can be obtained in a wide frequency band compared to a sound absorber having a single waveguide.
  • the waveguide 311 , the waveguide 314 , the waveguide 313 , and the waveguide 312 are superior in sound absorption coefficient in a low frequency band in that order.
  • the waveguide 312 , the waveguide 313 , the waveguide 314 , and the waveguide 311 are superior in sound absorption coefficient in a high frequency band in that order.
  • the sound absorbing unit 310 may be designed so that the frequency bands of sound waves absorbed by the waveguides do not overlap each other, or may be designed so that the frequency bands of the sound waves absorbed by the waveguides are partially overlapped.
  • the hole parameters in the through-hole region 321 may be uniform or may differ from portion to portion.
  • the hole parameters may be different for the portion in the perforated region 321 that is in contact with the space 341 (a portion overlapping the space 341 as viewed from the ⁇ D direction), the portion in the perforated region 321 that is in contact with the space 342 , the portion in the perforated region 321 that is in contact with the space 343 , and the portion in the perforated region 321 that is in contact with the space 344 , respectively.
  • the perforated region 321 there may be through holes that penetrate the perforated plate 320 and non-perforated holes that do not penetrate the perforated plate 320 (in other words, depressions existing on the ⁇ D direction side of the perforated plate 320 ).
  • the density of through holes may be different between a portion of the perforated region 321 contacting the space 341 and a portion of the perforated region 321 contacting the space 342 , while keeping the same density of holes combined through holes and non-through holes uniform. According to such a configuration, the uniformity of the design can be maintained by unifying the apparent number of holes in the perforated plate 320 , and the impedance can be matched with different hole parameters for each waveguide.
  • the total area of the non-perforated region 331 and the non-perforated region 332 of the surface of the perforated plate is larger than the area of the perforated region 321 .
  • This configuration allows the depth (i.e., thickness) of the sound absorbing unit 310 in the D direction to be reduced while improving the sound absorption coefficient in the low frequency band by increasing the length of the path where sound waves travel in a direction non-parallel to the D direction in each waveguide.
  • the shape of the perforated region 321 is a smooth rectangle in FIGS. 15 A and 15 B
  • the shape of the perforated region 321 is not limited to this, and may be other polygons or circles.
  • the perforated region 321 may be separated into a plurality of regions on the surface of the perforated plate 320 .
  • FIGS. 17 A and 17 B are diagrams showing an overview of a sound absorbing unit according to a modification.
  • FIGS. 18 A and 18 B are cross-sectional views of the HW section showing the structure of the sound absorbing unit according to the modification.
  • the length (thickness) in the D direction differs from part to part.
  • the sound absorbing unit 1010 described with reference to FIGS. 17 and 18 has a uniform length in the D direction.
  • the sound absorbing unit 1010 is provided with a perforated plate 1020 having a surface substantially parallel to the HW plane.
  • the perforated plate 1020 has a perforated region including a plurality of perforated regions 1021 , 1022 , 1023 , and 1024 , and a non-perforated region 1025 where no through-holes are formed.
  • the surface of the perforated plate 1020 (the surface on which the through-holes are present) is substantially parallel to the HW plane.
  • the perforated plate 1020 has a polygonal (more specifically, quadrangular) shape as viewed from the normal direction (D direction) of the perforated plate 1020 .
  • the perforated region of the perforated plate 1020 forms a triangular area connecting the center of the polygon, one vertex, and another point (specifically, one point on the side of the polygon) as viewed in the D direction.
  • the sound absorbing unit 1010 has a waveguide 1011 , a waveguide 1012 , a waveguide 1013 and a waveguide 1014 having different lengths.
  • the waveguides 1011 and 1012 are adjacent to each other across a sidewall 1012 b
  • the waveguides 1012 and 1013 are adjacent to each other across a sidewall 1013 b
  • the waveguides 1013 and 1014 are adjacent to each other across a side wall 1014 b . That is, the side wall 1012 b , the side wall 1013 b , and the side wall 1014 b divide the interior of the sound absorbing unit 1010 into a plurality of waveguides.
  • Each of the waveguide 1011 , waveguide 1012 , waveguide 1013 , and waveguide 1014 has a substantially trapezoidal (in other words, I-shaped) profile in the HW cross section.
  • the waveguides 1011 , 1012 , 1013 , and 1014 each extend in the width direction (W direction) of the sound absorbing unit 1010 and are arranged in parallel in the height direction (H direction) of the sound absorbing unit 1010 . That is, the waveguides 1011 , 1012 , 1013 and 1014 each extend non-parallel to the normal direction (D direction) of the perforated plate 1020 .
  • the sound absorbing unit 1010 has a shape with four-fold rotational symmetry as viewed in the D direction. That is, the sound absorbing unit 1010 has a total of four waveguides of the same shape for each of the waveguides 1011 , 1012 , 1013 , and 1014 . In addition, the sound absorbing unit 1010 has a total of four perforated regions of the same shape for each of the regions 1021 , 1022 , 1023 , and 1024 . A plurality of waveguides of the sound absorbing unit 1010 are arranged in directions (H direction and W direction) from the center of the perforated plate 1020 toward the periphery.
  • the sound absorbing unit 1010 may be configured as a whole, or may be configured by combining a plurality of members.
  • the sound absorbing unit 1010 may be configured by combining a plurality of resonators each having a waveguide and a perforated plate, or the sound absorbing unit 1010 may be configured by combining a perforated plate member and a waveguide member.
  • the perforated plate and the waveguide may be integrally configured. That is, the sound absorbing unit 1010 only needs to have a perforated surface with perforated regions and non-perforated regions, and a plurality of waveguides each in contact with a different area within the perforated region. Ventilation between the inside and the outside of each waveguide is possible through a plurality of through-holes present in the through-hole region adjacent to one end in the extension direction of the waveguide.
  • a portion near one end (the end in the +W direction) in the extension direction of the waveguide 1011 is in contact with the region 1021 and can be ventilated with the outside of the waveguide 1011 through a plurality of through-holes formed in the region 1021 .
  • a portion near the other end ( ⁇ W direction end) in the extending direction of the waveguide 1011 is not in contact with the perforated region, but is in contact with the non-perforated region 1025 Therefore, the portion cannot be ventilated with the outside of the waveguide 1011 .
  • the vicinity of one end (the end in the +W direction) of the waveguides 1012 , 1013 , and 1014 in the extending direction can be ventilated with the outside through a plurality of through-holes formed in is a region 1022 , a region 1023 , and a region 1024 , respectively.
  • the other end of each waveguide is in contact with the non-perforated region 1025 and is not ventilable to the outside.
  • the length of the portion of each waveguide that is in contact with the perforated region is half or less of the length in the extending direction of the waveguide.
  • the ratio of the length of the portion of the waveguide that is in contact with the perforated region is not limited to this, and it does not matter if at least the portion near one end in the extending direction of the waveguide is in contact with the perforated region.
  • the sound absorption characteristics of the sound absorbing unit 1010 in this embodiment are represented, for example, by the sound absorption coefficient or acoustic impedance for each frequency.
  • the sound absorbing unit 1010 may be designed so that the frequency bands of sound waves absorbed by the waveguides do not overlap each other, or the frequency bands of the sound waves absorbed by the waveguides are partially overlapped.
  • the length of waveguide 1011 is longer than the length of waveguide 1012
  • the length of waveguide 1012 is longer than the length of waveguide 1013
  • the length of waveguide 1013 is longer than the length of waveguide 1014 .
  • FIG. 19 A is a perspective view showing an overview of a modification of the sound absorbing unit.
  • FIGS. 20 A and 20 B are cross-sectional views showing the structure of a modification of the sound absorbing unit. While the sound absorbing unit 1010 described with reference to FIGS. 17 and 18 has a four-fold rotational symmetry, the perforated plate 1120 and internal structure of the sound absorbing unit 1110 shown in FIGS. 19 and 20 are not point symmetrical.
  • the sound absorbing unit 1110 is provided with a perforated plate 1120 having a surface substantially parallel to the HW plane.
  • Perforated plate 1120 includes a perforated region including regions 1121 , 1122 , 1123 and 1124 with multiple through-holes, a perforated region including regions 1126 , 1127 , 1128 and 1129 with multiple through-holes, and non-perforated region 1125 where no through-holes are formed.
  • the hole parameters for through-holes in the perforated region including areas 1121 - 1124 may be different than the hole parameters for through-holes in the perforated region including areas 1126 - 1129 .
  • the sound absorbing unit 1110 has a waveguide 1111 , a waveguide 1112 , a waveguide 1113 and a waveguide 1114 having different lengths. Also, the sound absorbing unit 1110 has a waveguide 1115 , a waveguide 1116 , a waveguide 1117 and a waveguide 1118 having different lengths. The waveguides 1111 to 1114 and the waveguides 1115 to 1118 are mutually different in at least one of length and shape.
  • Each of the waveguide 1111 , waveguide 1112 , waveguide 1113 , and waveguide 1114 has a substantially trapezoidal (in other words, I-shaped) profile in the HW cross section.
  • the waveguides 1111 to 1114 extend in the W direction or the H direction and are arranged in the direction from the center of the perforated plate 1120 toward the periphery.
  • Each of the waveguide 1115 , waveguide 1116 , waveguide 1117 , and waveguide 1118 has a shape in which the contour in the HW cross section is bent twice (in other words, a U shape).
  • the waveguides 1115 to 1118 have a portion extending in the W direction and a portion extending in the H direction, and are arranged in a direction from the center of the perforated plate 1120 toward the periphery.
  • the portions near one end of the waveguides 1111 , 1112 , 1113 , and 1114 in the extending direction can be vented to the outside through a plurality of through-holes formed in regions 1121 , 1122 , 1123 , and 1124 , respectively.
  • the portions near one end of the waveguides 1115 , 1116 , 1117 , and 1118 in the extending direction can be vented to the outside through a plurality of through-holes formed in regions 1126 , 1127 , 1128 , and 1129 , respectively.
  • the portion near the other end of each waveguide is in contact with the non-perforated region 1125 and is not ventilable to the outside.
  • the length in the extending direction of those waveguides can be made longer than the dimension in the W direction and the dimension in the H direction of the sound absorbing unit 1110 .
  • the sound absorbing unit 1110 has a non-rotationally symmetrical shape, there are many patterns of lengths and shapes of the waveguides included in the sound absorbing unit 1110 . Waveguides of different lengths and shapes have different sound absorption properties.
  • the sound absorbing unit 1110 compared with the sound absorbing unit 1010 having a rotationally symmetrical shape, a sound absorbing effect can be obtained in a wide frequency band.
  • the sound absorbing unit 1010 since it has a plurality of waveguides having the same sound absorbing characteristics, it is possible to obtain a higher sound absorbing effect in a specific frequency band than the sound absorbing unit 1110 does.
  • the sound absorbing unit 1010 shown in FIGS. 17 and 18 has a total of 16 waveguides
  • the sound absorbing unit 1110 shown in FIGS. 19 and 20 has a total of 8 waveguides.
  • the number of waveguides and the partitioning method inside the sound absorbing unit are not limited to these examples.
  • the number and arrangement of perforated regions in the perforated plate of the sound absorbing unit differ according to the number of waveguides that the sound absorbing unit has and how the inside of the sound absorbing unit is partitioned.
  • FIG. 21 A is a perspective view showing an overview of a modification of the sound absorbing unit.
  • FIGS. 22 A and 22 B are cross-sectional views showing the structure of a modification of the sound absorbing unit.
  • the interior of the sound absorbing unit 1010 described with reference to FIGS. 17 and 18 is partitioned by side walls extending from the center of the sound absorbing unit 1010 toward each vertex in the HW cross section.
  • the interior of the sound absorbing unit 1310 shown in FIGS. 21 and 22 is partitioned by side walls extending from the center of the sound absorbing unit 1310 toward each side in the HW cross section.
  • the sound absorbing unit 1310 has a shape with four-fold rotational symmetry as viewed in the D direction.
  • a perforated plate 1320 provided in the sound absorbing unit 1310 has a perforated region in which a plurality of through-holes are formed and a non-perforated region in which no through-holes are formed.
  • the sound absorbing unit 1310 has four waveguides each having four shapes with different lengths.
  • Each of the waveguides included in the sound absorbing unit 1310 has a shape in which the outline in the HW cross section is bent once (in other words, an L shape).
  • Each waveguide has a portion extending in the W direction and a portion extending in the H direction, and are aligned in a direction from the center to the periphery of the perforated plate 1320 .
  • a portion near one end in the extending direction of the waveguide of the sound absorbing unit 1310 can be ventilated with the outside through a plurality of through-holes formed in the perforated region of the perforated plate 1320 .
  • a portion in the vicinity of the other end in the extending direction of the waveguide is in contact with the non-perforated region and is not ventilable to the outside.
  • the sound absorbing unit 1310 since it has a plurality of types of waveguides with mutually different lengths, it is possible to obtain a sound absorbing effect in a wide frequency band. Furthermore, according to the sound absorbing unit 1310 , since it has a plurality of waveguides with approximately the same length, it is possible to obtain a high sound absorbing effect in a specific frequency band.
  • the sound absorbing unit 1310 shown in FIGS. 21 and 22 has a shape with four-fold rotational symmetry, but a sound absorbing unit may be configured by applying the structure described with reference to FIGS. 19 and 20 to the sound absorbing unit 1310 . Thereby, a sound absorbing effect can be obtained in a wider frequency band.
  • FIG. 23 A is a perspective view showing an overview of a modification of the sound absorbing unit.
  • FIGS. 24 A and 24 B are cross-sectional views showing the structure of a modification of the sound absorbing unit. While the sound absorbing unit 1010 described with reference to FIGS. 17 and 18 has a four-fold rotational symmetry, the perforated plate 1420 and internal structure of the sound absorbing unit 1410 shown in FIGS. 23 and 24 are not point symmetrical.
  • the external shape of the sound absorbing unit 1410 is a rhombus as viewed from the D direction.
  • the sound absorbing unit 1410 is provided with a perforated plate 1420 having a surface substantially parallel to the HW plane.
  • the perforated plate 1420 has a perforated region 1421 in which a plurality of through-holes are formed and a non-perforated region 1425 in which no through-holes are formed.
  • the perforated plate 1420 has a rectangular shape as viewed from the normal direction (D direction) of the perforated plate 1420 .
  • the perforated region of the perforated plate 1420 forms a triangular area connecting the three vertices of the quadrangle as viewed from the D direction.
  • the sound absorbing unit 1410 has multiple waveguides of different lengths.
  • Each of the waveguides included in the sound absorbing unit 1410 has a shape in which the contour in the HW cross section is bent once (in other words, an L shape).
  • the multiple waveguides of the sound absorbing unit 1410 extend in a direction non-parallel to the D direction and are arranged in a direction non-parallel to the D direction.
  • a portion near one end in the extending direction of each waveguide of the sound absorbing unit 1410 can be ventilated with the outside through a plurality of through-holes formed in the through-hole region 1421 .
  • the portion near the other end of each waveguide is in contact with the non-perforated region 1425 and is not ventilable to the outside.
  • a waveguide included in the sound absorbing unit 1410 extends in a direction substantially perpendicular to the D direction and has a bent shape. Therefore, the length of at least one of the plurality of waveguides included in the sound absorbing unit 1410 in the extending direction is made longer than any of the W, H, and D dimensions of the sound absorbing unit 1410 . be able to. With such a configuration, it is possible to reduce the size of the sound absorbing unit 1410 while improving the sound absorption coefficient in the low frequency band by increasing the length of the waveguide in the extending direction. Moreover, according to the sound absorbing unit 1410 , it is possible to increase the difference in the length of the plurality of waveguides in the extending direction while arranging the plurality of waveguides in parallel. As a result, a well-balanced sound absorption effect can be obtained in a wide frequency band from low frequency bands to high frequency bands.
  • FIG. 25 A is a perspective view showing an overview of a modification of the sound absorbing unit.
  • FIGS. 26 A and 26 B are cross-sectional views showing the structure of a modification of the sound absorbing unit.
  • the outer shape of the sound absorbing unit 1010 described with reference to FIGS. 17 and 18 is a quadrangle as viewed from the D direction.
  • the outer shape of the sound absorbing unit 1510 shown in FIGS. 25 and 26 is substantially circular as viewed from the D direction.
  • the sound absorbing unit 1510 has a shape with four-fold rotational symmetry as viewed in the D direction.
  • a perforated plate 1520 provided in the sound absorbing unit 1510 has a perforated region 1521 having a plurality of through-holes and a non-perforated region 1525 having no through-holes.
  • the perforated plate 1520 has a circular shape as viewed from the normal direction (D direction) of the perforated plate 1520 .
  • the perforated region of the perforated plate 1520 forms a fan-shaped area connecting the center of the circle and two points on the circumference as viewed from the D direction.
  • the sound absorbing unit 1510 has four waveguides each having four shapes with different lengths.
  • Each of the waveguides included in the sound absorbing unit 1510 has an arc-shaped contour in the HW cross section.
  • Each waveguide extends in the circumferential direction of the sound absorbing unit 1510 as viewed from direction D, and is arranged concentrically in the direction from the center of the perforated plate 1520 toward the periphery.
  • a portion near one end in the extending direction of the waveguide of the sound absorbing unit 1510 can ventilate with the outside through a plurality of through-holes formed in the perforated region 1521 of the perforated plate 1520 .
  • a portion near the other end in the extending direction of the waveguide is in contact with the non-perforated region 1525 and is not ventilable to the outside.
  • the sound absorbing unit 1510 Since the sound absorbing unit 1510 has a plurality of types of waveguides with different lengths, it is possible to obtain a sound absorbing effect in a wide frequency band. Furthermore, according to the sound absorbing unit 1510 , since it has a plurality of waveguides with approximately the same length, it is possible to obtain a high sound absorbing effect in a specific frequency band.
  • the sound absorbing unit 1510 shown in FIGS. 25 and 26 has a shape with four-fold rotational symmetry, by applying the structure described using FIGS. 19 and 20 to the sound absorbing unit 1510 , a sound absorbing unit with a shape that is not rotationally symmetrical may be constructed. Thereby, a sound absorbing effect can be obtained in a wider frequency band.
  • FIGS. 27 A and 27 B are diagrams showing an overview and structure of a modification of the sound absorbing unit.
  • FIGS. 28 and 29 are diagrams showing structures of modifications of the sound absorbing unit.
  • each waveguide extends substantially linearly, whereas the sound absorbing unit 1610 shown in FIGS. 27 through 30 includes a plurality of waveguides with different numbers of bends.
  • the sound absorbing unit 1610 is provided with a perforated plate 1620 having a surface substantially parallel to the HW plane.
  • the perforated plate 1620 has a plurality of perforated regions 1621 each having a plurality of through-holes and a non-perforated region 1625 having no through-holes.
  • the hole parameters of through-holes in multiple through-hole regions 1621 may be different from each other.
  • FIG. 27 B shows a front view of the sound absorbing unit 1610 through the perforated plate 1620 so that the internal structure of the sound absorbing unit 1610 (especially the shape of the waveguide) can be easily understood.
  • FIG. 28 shows the inside of the sound absorbing unit 1610 and the perforated plate 1620 seen through from the rear surface of the sound absorbing unit 1610 .
  • the sound absorbing unit 1610 includes a plurality of waveguides 1611 , 1612 , 1613 , 1614 , 1615 , 1616 , 1617 , and 1618 having different lengths. Further, the sound absorbing unit 1610 has a shape with four-fold rotational symmetry, and has three other waveguides of the same shape for each of the waveguides 1611 through 1618 .
  • Each of the waveguides 1611 to 1614 has a linear contour (in other words, an I shape) in the HW cross section.
  • Each of the waveguides 1615 to 1618 has a portion extending in the W direction and a portion extending in the H direction, and the profile in the HW cross section is bent twice (in other words, a U shape).
  • the portions near one end in the extending direction of waveguides 1611 to 1618 can be vented to the outside via a plurality of through-holes formed in through-hole region 1621 , respectively.
  • the portion near the other end of each waveguide is in contact with the non-perforated region 1625 and is not ventilable to the outside.
  • the length in the extending direction of these waveguides can be longer than the dimension in the W direction and the dimension in the H direction of the sound absorbing unit 1610 .
  • the sound absorbing unit 1610 also has a short waveguide that is not bent. This increases the pattern of lengths and shapes of waveguides included in the sound absorbing unit 1610 . Waveguides of different lengths and shapes have different sound absorption properties. Therefore, according to the sound absorbing unit 1610 , compared to the sound absorbing unit 1010 in which each waveguide has the same number of bends, a sound absorbing effect can be obtained in a wide frequency band.
  • FIG. 29 A is a side view of the sound absorbing unit 1610 viewed from direction H
  • FIG. 29 B is a transparent side view of the sound absorbing unit 1610 so that the internal structure of the sound absorbing unit 1610 can be easily understood.
  • a recessed notch 1630 is provided on the outer shape of the side surface of the sound absorbing unit 1610 . Since the sound absorbing unit 1610 has the notch 1630 , a sound absorbing wall using the sound absorbing unit 1610 can be easily created.
  • FIGS. 30 A and 30 B are diagrams showing the structure of a sound absorbing wall using the sound absorbing unit 1610 .
  • a sound absorbing wall 1600 is created by fitting sound absorbing units 1610 into each of a plurality of spaces 1602 surrounded by frames 1601 .
  • the sound absorbing unit 1610 is fixed to the frame 1601 by fitting the notch 1630 of the sound absorbing unit 1610 with the projection of the frame 1601 .
  • the plurality of sound absorbing units 1610 are arranged such that the normal directions of the plurality of perforated plates 1620 of the plurality of sound absorbing units 1610 are substantially parallel to each other.
  • the sound absorbing unit 1610 may be fitted in only part of the plurality of spaces 1602 that the frame 1601 has.
  • the plurality of sound absorbing units included in the sound absorbing wall 1600 may have different structures.
  • the sound absorbing wall 1600 may be configured by providing the sound absorbing unit of each of the above-described embodiments and modifications with the notch 1630 and combining a plurality of types of sound absorbing units with the frame 1601 .
  • FIG. 31 A is a perspective view showing an overview of a modification of the sound absorbing unit.
  • FIG. 31 B is a front view showing an overview of a modification of the sound absorbing unit.
  • FIG. 32 A is a semi-transparent perspective view to facilitate understanding of the structure of the modification of the sound absorbing unit.
  • FIG. 32 B is a front view to facilitate understanding of the structure of the modification of the sound absorbing unit. While the sound absorbing unit 1010 described with reference to FIGS.
  • the sound absorbing unit 1710 has a four-fold rotational symmetry, the perforated plate 1720 and internal structure of the sound absorbing unit 1710 shown in FIGS. 31 and 32 are not point symmetrical. Also, the sound absorbing unit 1710 includes a plurality of waveguides with different numbers of bends.
  • the sound absorbing unit 1710 is provided with a perforated plate 1720 having a surface substantially parallel to the HW plane.
  • the perforated plate 1720 has a plurality of perforated regions 1721 each having a plurality of through-holes and a non-perforated region 1725 having no through-holes.
  • the hole parameters of through-holes in multiple through-hole regions 1721 may be different from each other.
  • the sound absorbing unit 1710 has multiple waveguides of different lengths.
  • Each of waveguide 1716 , waveguide 1717 , waveguide 1718 , and waveguide 1719 has a linear (in other words, I-shaped) contour in the HW cross section.
  • Each of the waveguides 1711 , 1714 , and 1701 has a portion extending in the W direction and a portion extending in the H direction, and the profile in the HW cross section is bent once (in other words, and L-shaped).
  • Each of the waveguides 1712 , 1713 , and 1715 has a portion extending in the W direction and a portion extending in the H direction, and the profile in the HW cross section is bent twice (in other words, and U-shaped).
  • a portion near one end in the extending direction of each waveguide can ventilate with the outside through a plurality of through-holes formed in the through-hole region 1721 .
  • the portion near the other end of each waveguide is in contact with the non-perforated region 1725 and is not ventilable to the outside.
  • Some waveguides included in the sound absorbing unit 1710 extend in a direction substantially perpendicular to the D direction and have a bent shape. Therefore, the length of at least one of the plurality of waveguides included in the sound absorbing unit 1710 in the extending direction can be longer than any of the W, H, and D dimensions of the sound absorbing unit 1710 . With such a configuration, it is possible to reduce the size (especially the thickness in the D direction) of the sound absorbing unit 1710 while improving the sound absorption coefficient in the low frequency band by increasing the length of the waveguide in the extending direction. Also, the sound absorbing unit 1710 has a waveguide that is not bent, a waveguide that is bent once, and a waveguide that is bent twice.
  • Waveguides of different lengths and shapes have different sound absorption properties. Therefore, according to the sound absorbing unit 1710 , compared with the sound absorbing unit 1010 in which each waveguide has the same number of bends, it is possible to obtain a sound absorbing effect in a wide frequency band.
  • the sound absorbing unit has a combination of multiple waveguides with different shapes and sizes and a combination of multiple waveguides with substantially the same shape and size.
  • the present embodiment is not limited to this, and the sound absorbing unit only needs to have a cavity surrounded by an outer shell and a through-hole that communicates the inside and the outside of the cavity. That is, the sound absorbing unit only needs to have at least one space in which air resonates, and it is not essential that the sound absorbing unit has a partition wall that divides the internal space.
  • the number of cavities and the number of through-holes that the sound absorbing unit has may be one or more.
  • the sound absorbing unit has a plurality of cavities (waveguides) that are mutually different in at least one of shape and size, sound in a wider frequency band can be absorbed.
  • the plurality of waveguides of the sound absorbing unit have different through-hole arrangements, but the present embodiment is not limited to this, and the sound absorbing unit may include a plurality of waveguides having the same through-hole arrangement.
  • the sound absorbing unit By providing the sound absorbing unit with two or more waveguides having mutually different resonance characteristics, sound in a wide frequency band can be absorbed. On the other hand, if some of the plurality of waveguides of the sound absorbing unit have resonance characteristics close to each other, the sound absorption coefficient in a specific frequency band can be improved.
  • the length of the waveguide in the direction normal to the surface of the perforated plate is assumed to be non-uniform.
  • the thickness of the sound absorbing unit 10 in the D direction is thicker at the central portion seen from the ⁇ D direction than at the peripheral edge seen from the ⁇ D direction.
  • the volume of each waveguide can be increased compared to the case where the thickness of the sound absorbing unit 10 is made equal to the thickness of the peripheral portion as viewed from the ⁇ D direction, thereby sound absorption performance in the frequency band can be improved.
  • the thickness in the D direction of the sound absorbing unit 10 is not limited to this, and may be uniform. In this case, the length of the waveguide in the direction normal to the surface of the perforated plate is also uniform.
  • the cavity portion (waveguide) is formed by the perforated plate and the base body (chamber member) integrally fixed to the perforated plate.
  • the perforated plate provided in the sound absorbing unit may be configured to be detachable from the chamber member. That is, the sound absorbing unit may be composed of a three-dimensional member having a plurality of waveguides and a perforated plate that can be attached to the three-dimensional member. As a result, even when the perforated plate is worn out and the sound absorption characteristics of the sound absorbing unit deteriorate, the perforated plate can be easily replaced to improve the sound absorption characteristics of the sound absorbing unit.
  • the sound absorption characteristics of the sound absorbing unit can be arbitrarily adjusted.
  • the partition wall that divides the internal space of the sound absorbing unit may be provided in the chamber member or the perforated plate, or independent of both the chamber member and the chamber member.
  • At least one of the perforated plate and the partition provided in the sound absorbing unit may be configured to be movable. Also, a new member may be added inside the waveguide. This makes it easy to adjust the shape and size of the waveguide, and allows the sound absorption characteristics of the sound absorbing unit to be adjusted arbitrarily.
  • the number of waveguides included in the sound absorbing unit is not limited to the above example, and the sound absorbing unit may have a plurality of waveguides that differ in at least one of shape and length.
  • the sound absorbing unit has a hexagonal shape as viewed from the ⁇ D direction, a perforated surface is provided on the surface of the sound absorbing unit on the ⁇ D direction side, and the interior of the sound absorbing unit is divided into multiple cavities by partition walls.
  • the shape of the sound absorbing unit may be other polyhedrons or spheres.
  • the perforated surface may be provided on another surface of the sound absorbing unit.
  • the perforated surface may be provided only on a part of one surface of the sound absorbing unit, or may be provided on a plurality of surfaces of the sound absorbing unit.
  • the inside of the sound absorbing unit may contain a structure other than the cavity.
  • a plurality of sound absorbing units having the same shape may be arranged side by side, or a plurality of sound absorbing units having different shapes may be arranged side by side.
  • multiple types of sound absorbing units described in the above-described embodiment and modifications may be arranged side by side.
  • a plurality of sound absorbing units having the same waveguide shape but different hole parameters of the perforated plate may be arranged side by side.
  • a sound absorbing effect can be obtained in a wider frequency band than when the same sound absorbing units are arranged side by side.
  • a higher sound absorbing effect can be obtained in a specific frequency band than when a plurality of sound absorbing units having different sound absorption characteristics are arranged side by side.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Multimedia (AREA)
  • Electromagnetism (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
  • Building Environments (AREA)
  • Devices Affording Protection Of Roads Or Walls For Sound Insulation (AREA)
US18/296,656 2021-08-06 2023-04-06 Sound absorber, sound absorbing panel and sound absorbing wall Active US11854523B2 (en)

Applications Claiming Priority (7)

Application Number Priority Date Filing Date Title
JP2021-129497 2021-08-06
JP2021129497 2021-08-06
JP2021-196557 2021-12-02
JP2021196557 2021-12-02
JP2022036141 2022-03-09
JP2022-036141 2022-03-09
PCT/JP2022/026161 WO2023013323A1 (ja) 2021-08-06 2022-06-30 吸音部材、吸音パネル及び吸音壁

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2022/026161 Continuation WO2023013323A1 (ja) 2021-08-06 2022-06-30 吸音部材、吸音パネル及び吸音壁

Publications (2)

Publication Number Publication Date
US20230260496A1 US20230260496A1 (en) 2023-08-17
US11854523B2 true US11854523B2 (en) 2023-12-26

Family

ID=83691951

Family Applications (1)

Application Number Title Priority Date Filing Date
US18/296,656 Active US11854523B2 (en) 2021-08-06 2023-04-06 Sound absorber, sound absorbing panel and sound absorbing wall

Country Status (4)

Country Link
US (1) US11854523B2 (ja)
EP (1) EP4213144A4 (ja)
JP (3) JP7157974B1 (ja)
CN (1) CN116134195A (ja)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0962267A (ja) 1995-08-25 1997-03-07 Nok Megurasutikku Kk 吸音材
JP2009030432A (ja) 2007-06-28 2009-02-12 Yamaha Corp 吸音構造体および音響室並びに室内音響特性調整方法
JP2017115572A (ja) 2015-12-18 2017-06-29 中日本高速道路株式会社 防音パネル及び防音壁
US20190122649A1 (en) * 2016-04-25 2019-04-25 Acoustic Metamaterials Group Limited Broadband acoustic absorption metamaterials
US20190213990A1 (en) * 2016-08-19 2019-07-11 3M Innovative Properties Company Sound-absorbing panels comprising a core consisting of connected cells, wherein some of the cell walls have openings
US20190264614A1 (en) * 2016-11-14 2019-08-29 Safran Acoustic attenuation panel comprising a front skin and a central structure
US20210115664A1 (en) * 2019-10-18 2021-04-22 The Regents Of The University Of Michigan Acoustic device thermoforming
CN112712784A (zh) * 2020-11-30 2021-04-27 南京大学 一种低频宽带平板吸声结构

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3475917B2 (ja) * 2000-07-13 2003-12-10 ヤマハ株式会社 音響放射構造体および音響室
JP5957622B2 (ja) * 2014-01-28 2016-07-27 日本板硝子環境アメニティ株式会社 吸音パネル及び防音壁設備
JP6524133B2 (ja) * 2017-03-24 2019-06-05 イビデン株式会社 吸音材
TW201923200A (zh) * 2017-08-11 2019-06-16 泰奇想股份有限公司 複合式吸音板
CN109285534A (zh) * 2018-11-06 2019-01-29 株洲国创轨道科技有限公司 吸声装置

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0962267A (ja) 1995-08-25 1997-03-07 Nok Megurasutikku Kk 吸音材
JP2009030432A (ja) 2007-06-28 2009-02-12 Yamaha Corp 吸音構造体および音響室並びに室内音響特性調整方法
JP2017115572A (ja) 2015-12-18 2017-06-29 中日本高速道路株式会社 防音パネル及び防音壁
US20190122649A1 (en) * 2016-04-25 2019-04-25 Acoustic Metamaterials Group Limited Broadband acoustic absorption metamaterials
US20190213990A1 (en) * 2016-08-19 2019-07-11 3M Innovative Properties Company Sound-absorbing panels comprising a core consisting of connected cells, wherein some of the cell walls have openings
US20190264614A1 (en) * 2016-11-14 2019-08-29 Safran Acoustic attenuation panel comprising a front skin and a central structure
US20210115664A1 (en) * 2019-10-18 2021-04-22 The Regents Of The University Of Michigan Acoustic device thermoforming
CN112712784A (zh) * 2020-11-30 2021-04-27 南京大学 一种低频宽带平板吸声结构

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
Decision to Grant a Patent dated Sep. 27, 2022, in corresponding Japanese Patent Application No. 2022-548389, 5 pages.
International Search Report dated Sep. 6, 2022, in corresponding International Patent Application No. PCT/JP2022/026161, 5 pages.
Notice of Reasons for Refusal dated Aug. 25, 2022, in corresponding Japanese Patent Application No. 2022-548389, 9 pages.
Wu et al., "Low-frequency sound absorption of hybrid absorber based on micro-perforated panel and coiled-up channels" Applied Physics Letters 114, 151901 (Apr. 16, 2019); doi: 10.1063/1.5090355, 6 pages.

Also Published As

Publication number Publication date
US20230260496A1 (en) 2023-08-17
EP4213144A4 (en) 2023-11-01
JP7157974B1 (ja) 2022-10-21
JP2023024421A (ja) 2023-02-16
EP4213144A1 (en) 2023-07-19
CN116134195A (zh) 2023-05-16
JPWO2023013323A1 (ja) 2023-02-09
JP2023027207A (ja) 2023-03-01
JP7197876B1 (ja) 2022-12-28

Similar Documents

Publication Publication Date Title
JP5531343B2 (ja) 間仕切りパネル
JP5691197B2 (ja) 音響構造体、プログラムおよび設計装置
JP2007100394A (ja) 吸音パネル
EP2402936B1 (en) Acoustic structure
JP2002030744A (ja) 音響放射構造体、音響室および音響散乱方法
US11854523B2 (en) Sound absorber, sound absorbing panel and sound absorbing wall
JPH06158751A (ja) 音響吸音体
WO2023013323A1 (ja) 吸音部材、吸音パネル及び吸音壁
JP7246053B1 (ja) 吸音パネル及び吸音壁
CN114981883A (zh) 吸音构造体和吸音壁
GB2573056A (en) Speaker and sound diffuser thereof
WO2023021916A1 (ja) 吸音部材及び吸音壁
CN103428612B (zh) 扬声器
JP2013088794A (ja) 制音構造体
KR20160012840A (ko) 방음벽 패널
JP3209661B2 (ja) 共鳴型吸音板
JP2022180196A (ja) 吸音部材
KR102635232B1 (ko) 흡음률을 향상시킨 투명방음패널
JP2023006879A (ja) 吸音ユニットおよび吸音ユニットの製造方法
JP7373360B2 (ja) 音響調整構造体
JP2022056897A (ja) 仕切りパネル
JPH11107225A (ja) 吸音パネル
JP2023088253A (ja) 吸音ユニットおよびこれを備える吸音構造体並びに自動車用内装部品
JP2023115604A (ja) 構造体および該構造体を含む吸音材等
JP2023085932A (ja) 吸音部材

Legal Events

Date Code Title Description
FEPP Fee payment procedure

Free format text: ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: BIG.); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY

AS Assignment

Owner name: PIXIE DUST TECHNOLOGIES, INC., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GOMI, MASAKI;TAIRA, YUDAI;SIGNING DATES FROM 20230314 TO 20230320;REEL/FRAME:063262/0873

FEPP Fee payment procedure

Free format text: ENTITY STATUS SET TO SMALL (ORIGINAL EVENT CODE: SMAL); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY

STPP Information on status: patent application and granting procedure in general

Free format text: NON FINAL ACTION MAILED

STPP Information on status: patent application and granting procedure in general

Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER

STPP Information on status: patent application and granting procedure in general

Free format text: NOTICE OF ALLOWANCE MAILED -- APPLICATION RECEIVED IN OFFICE OF PUBLICATIONS

STPP Information on status: patent application and granting procedure in general

Free format text: PUBLICATIONS -- ISSUE FEE PAYMENT RECEIVED

STPP Information on status: patent application and granting procedure in general

Free format text: PUBLICATIONS -- ISSUE FEE PAYMENT VERIFIED

STCF Information on status: patent grant

Free format text: PATENTED CASE